Police officers involved in a "serious, gratuitous and prolonged" attack on a British Muslim man that led the Metropolitan police to pay £60,000 in damages this week have been accused of dozens of previous assaults against black or Asian men.

Babar Ahmad, 34, a terrorist suspect, was punched, kicked, stamped on and strangled during his arrest by officers from one of the Met's territorial support groups at his London home in December 2003.

After six years of denials from Scotland Yard, lawyers acting for the Metropolitan police commissioner, Sir Paul Stephenson, were forced to admit in the high court that Ahmad had been the victim of sustained and gratuitous violence during his arrest and agreed to pay £60,000 in damages.

But the Guardian can reveal that the Met was aware for years that the six officers involved were the subject of repeated complaints. According to documents submitted to the court, four of the officers who carried out the raid on Ahmad's home had 60 allegations of assault against them - of which at least 37 were made by black or Asian men. One of the officers had 26 separate allegations of assault against him - 17 against black or Asian men.

The Met has confirmed that since 1992 all six officers involved in the Ahmad assault had been subject to at least 77 complaints. When lawyers for Ahmad asked for details of these allegations it emerged that the police had "lost" several large mail sacks detailing at least 30 of the complaints.